The present invention relates to the preparation of a haloacylated aniline compound. The compounds prepared in accordance with the process of the present invention are especially useful as fungicides.
The preparation of haloacylated aniline compounds is described in various references. For example, U.S. Pat. No. 3,268,584 relates to the preparation of various alpha-haloanilines. The Olin U.S. Pat. No. 3,268,584 states at column 3, lines 31 to 60:
"The alpha-haloacetanilides of this invention may in general be prepared by haloacetylation of suitable N-substituted and ortho-substituted aromatic amines, which may be prepared for example, by the process disclosed in application Ser. No. 824,455, filed July 2, 1959, now abandoned, from a primary aromatic amine and a branch-chain olefin. The haloacetylating agent is preferably either a haloacetic anhydride, such as chloroacetic anhydride, or a haloacetyl halide, such as chloroacetyl chloride, bromoacetyl bromide, or the like." PA1 "The haloacetylation reaction is preferably conducted in the presence of a suitable liquid reaction medium. The liquid reaction medium must be anhydrous if the acetylating agent is a haloacetic anhydride; however, either anhydrous reaction mediums or mediums containing water can be used with haloacetyl halide acetylating agents. Examples of some suitable reaction mediums for use with either acetylating agent include benzene, diethyl ether, hexane, methylethyl ketone, chlorobenzene, toluene, chloroform, and the xylenes. Since an acid or hydrogen halide is eliminated in the haloacetylation reaction, it is also desirable to have an acid acceptor present in the reaction zone to neutralize the acid formed. Suitable acid acceptors for anhydrous solvent systems include the N-substituted ortho-substituted aromatic amine reactants, which may be present in the reaction zone in an amount greater than that required for the acetylation, tertiary amines, and pyridine. Acid acceptors in aqueous solvent systems include alkali or alkaline earth hydroxides and alkali or alkaline earth metal carbonates or bicarbonates." PA1 "is generally purified by conventional procedures, e.g., extraction, distillation or crystallization, before use in the acylation reaction (2)." PA1 "The acylation reaction (2) is conducted by conventional procedures in the presence of an organic amine such as a trialkyl amine or a pyridine compound. The reactants (IV) and (V) and the amine are generally contacted in substantially equimolar amounts in an inert organic solvent at a temperature of 0.degree. to 100.degree. C. Suitable inert organic solvents include ethyl acetate, methylene dichloride, dimethoxyethane, benzene, etc."
As will be noted from the above, the Olin U.S. Pat. No. 3,268,584 teaches that it is desirable to have an acid acceptor present in the reaction zone wherein the haloacylation is conducted.
U.S. Pat. No. 3,345,151 also relates to the preparation of alpha-haloacetanilides and also teaches that the acylation reaction should be carried out in the presence of an acid acceptor.
U.S. Pat. No. 4,008,066 discloses the preparation of compounds of the formula ##STR2##
This U.S. Pat. No. 4,008,066 also teaches that the acylation reaction used to form the above compound advantageously is carried out in the presence of an acid acceptor, especially if chloroacetyl halides are used. The '066 patent states that it is possible to use an excess of the aniline compound which is being acylated as the acid acceptor. In Example 1 of the '066 patent, 2,6-dimethylaniline acetic acid methyl amide is acylated to form N-methyl-[N'-2,6-dimethylphenyl)-N'-chloroacetylamino]-acetamide by the reaction of the dimethylaniline with chloroacetyl chloride at a temperature of 110.degree. C. From the amount of reactants used in the example, it is seen that a yield of about 50 mol percent is obtained with evidently 50% of the aniline compound fed to the acylation reaction being tied up as an acid acceptor.
U.S. Pat. No. 4,025,648 and German patent application No. 2,350,944 both relate to dimethylanilines having substituted on the aniline nitrogen a propionic acid methyl group and an alpha-halo acyl group. The disclosures of these references are similar but in the German reference the acyl group is acetyl whereas in U.S. Pat. No. 4,025,648 the acyl group is propionyl or higher. According to column 3 of the '648 patent, and similary in the last paragraph of page 13 of the German reference, preferably the acylation reaction used to form the acyl-substituted aniline compound is carried out in the presence of an acid acceptor such as trialkylamine, pyridine or an inorganic base such as a hydroxide or carbonate of an alkali metal. The '648 patent indicates that it is especially desirable to use an acid acceptor when the acylation is carried out using a haloacyl halide.
The use of an acid acceptor is not as critical when an acid anhydride is used for the acylation reaction because the resulting acid such as chloroacetic acid is much weaker than hydrogen chloride which results from the use of a chloroacyl for the acylation reaction. Thus, U.S. Pat. No. 3,875,228, Example 1, paragraph B shows a yield of about 72% for an acylation reaction carried out at about 100.degree. C. when 4-isopropylamino indane is acylated with chloroacetic acid anhydride in the absence of an added acid acceptor.
The term "added acid acceptor" is used herein to mean a species which is added or fed to the reaction zone other than the feed aniline compound as, for example, an added tertiary amine which is capable of tying up hydrogen chloride acid released from the acylation reaction.
U.S. Pat. No. 3,933,860 to Chan discloses the preparation of haloacylated aniline compounds in the following reaction sequence: ##STR3##
According to the Chan U.S. Pat. No. 3,933,860, the product (IV) of alkylation reaction (1):